1. Field of the Invention
The present invention relates generally to catheter distal end assemblies, and more particularly to surface coatings for such assemblies.
2. Description of the Prior Art
Conventionally, catheter components such as electrodes and thermocouples are placed onto electrophysiology catheters manually. The electrodes are then held in position and masked with adhesive. This process is very time consuming and thus quite expensive. An undesirable feature of such a catheter-electrode construction for ablation is that it has high electrode edge effects that are attributed to delivering RF energy to an electrode having a sharp transition between the conductive electrode and the insulating catheter body. A further limitation in the prior art is that toxic materials such as those composed of silver and lead, cannot be used where direct contact with the patient""s tissues and bodily fluids occur. Additionally, many prior art catheter devices are formed with small openings and crevices which permit the ingress and retention of bodily fluids and tissue. There is therefore a need for a surface coating for catheter distal end assemblies that solves these problems.
A catheter of the present invention includes a distal end assembly having an external surface coating. Where the distal end assembly includes electrodes or other electrical components, the coating is preferably electrically conductive. In the preferred embodiment, such an electrically conductive coating is formed from a material comprising regenerated cellulose, although other materials such as a hydrogel or a plastic having an electrically conductive component are utilizable. Where the distal end assembly includes optical or ultrasonic components, the preferred surface coating is substantially transparent to optical and ultrasonic transmissions therefrom. A regenerated cellulose coating is suitable for both optical and ultrasonic distal end assemblies.
The robustness of the surface coating permits the manufacture and utilization of electrode configurations that are formed on a non-conductive base member by processes such as pad printing, vapor deposition, ion beam assisted deposition, electroplating and other printed circuit manufacturing processes. Additionally, because the surface coating produces a smooth outer surface to the distal end assembly, lead wires and temperature sensing devices can be bonded to the exterior surface of electrodes and then coated to produce a smooth outer surface; thus providing a simple, inexpensive manufacturing method for the attachment of such components to the electrodes.
It is an advantage of the present invention that catheter distal end assemblies can be more efficiently manufactured.
It is another advantage of the present invention that catheter distal end assemblies can be more inexpensively manufactured.
It is a further advantage of the present invention that electrode configurations can be printed or deposited upon the surface of a catheter end assembly and withstand the mechanical and chemical stresses of usage without degradation.
It is yet another advantage of the present invention that catheter distal end assemblies having a surface coating are sealed against ingress of contaminating bodily fluids.
These and other features and advantages of the present invention will become obvious to those of ordinary skill in the art upon reading the following detailed description.